commit 67c9e026899bf8b5c46363ccd26fa74598c83f67
author Tom Sepez <tsepez@chromium.org> Tue Mar 26 20:36:38 2019 +0000
committer Chromium commit bot <commit-bot@chromium.org> Tue Mar 26 20:36:38 2019 +0000
tree 5e13b8b568dabeb49f62c6c076919ec71e37986c
parent db121ec5abd699833d5d778510bb4ed757a3ba1b

Avoid undefined negation in CFGAS_Decimal.FromInt32.

Allows test to run under UBSAN without warnings being logged.

Thanks to the charming quirks of C++ signed arithmetic, negating
std::numeric_limits<int>::min() isn't allowed. Instead, in a two's
complement world, at least it is its own inverse ...

Change-Id: Ie03a7e9b2a54a87ad7d6b6e6107154bcd0c60b81
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/52391
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

xfa/fgas/crt/cfgas_decimal.cpp

diff --git a/xfa/fgas/crt/cfgas_decimal.cpp b/xfa/fgas/crt/cfgas_decimal.cpp
index ea6a45f..701cda8 100644
--- a/xfa/fgas/crt/cfgas_decimal.cpp
+++ b/xfa/fgas/crt/cfgas_decimal.cpp
@@ -7,6 +7,7 @@
 #include "xfa/fgas/crt/cfgas_decimal.h"
 
 #include <algorithm>
+#include <limits>
 #include <utility>
 
 #include "core/fxcrt/fx_extension.h"
@@ -253,6 +254,9 @@
 CFGAS_Decimal::CFGAS_Decimal(int32_t val) {
   if (val >= 0) {
     *this = CFGAS_Decimal(static_cast<uint32_t>(val));
+  } else if (val == std::numeric_limits<int32_t>::min()) {
+    *this = CFGAS_Decimal(static_cast<uint32_t>(val));
+    SetNegate();
   } else {
     *this = CFGAS_Decimal(static_cast<uint32_t>(-val));
     SetNegate();